Local anesthetics block nerve conduction when applied locally to nerve tissue. They may act on any part of the nervous system and on every type of nerve fiber or they may act selectively between different types of nervous tissue such as central nervous tissue or peripheral nervous tissue or myelinated or non-myelinated fibers. The advantage with useful local anesthetics is that their action is reversible and nerve function is restored with no evidence of structural damage to nerve fibers or cells. Continued studies have been carried out in research to develop drugs which would have all the desirable properties of a good local anesthetic agent. Such properties would necessarily be non-irritating to the tissue with which it is in contact or cause any permanent damage to nerve structure. Further, its systemic toxicity should be low. The ideal local anesthetic should be effective regardless whether it is injected into the tissue or applied locally to mucous membranes. The time for onset should also be as short as possible while its action should last long enough for the need indicated, and the recovery period should be one which is of a suitable duration.
Anti-arrhythmic agents have been long sought by the researchers. The principal anti-arrhythmic drugs of long established usefulness are quinidine and procainamide. More recently lidocaine, phenytoin and propranolol have been found to be helpful in establishing certain anti-arrhythmic disorders. Each of these agents, however, has been found to have certain drawbacks and great care must be used when they are employed for the treatment of arrhythmic disorders. The ideal anti-arrhythmic agent would be one having a minimal amount of side effects while at the same time being orally active, typical side effect being myocardial depression and CNS deficit. The most serious form of arrhythmia is fibrillation and a high degree of protection against this particular disorder would be most beneficial.
We have unexpectedly found potent anti-arrhythmic and local anesthetic agents.
We have unexpectedly found a class of chemical compounds which have anti-arrhythmic and local anesthetic properties without accompanying side effects which are common with these agents.
We have further found unexpectedly that amidinourea compounds are effective anti-arrhythmic agents which act orally.
We have also unexpectedly found a means of providing protection against fibrillation.
We have also unexpectedly found that administration of amidinoureas is a simple and effective method for the treatment of anti-arrhythmic disorders.
We have still further found effective local anesthetic agents which are non-irritating to the tissue, do not cause permanent damage to their structure, their systemic toxicity is low, and they are effective when applied by injection into the tissue or applied locally. These agents have also been found to have a desirable onset period while their action may be extended for periods of time depending on the use intended.